Promoting Photocatalytic Activity of NH2-MIL-125(Ti) for H2 Evolution Reaction through Creation of TiIII- and CoI-Based Proton Reduction Sites

• DOI: 10.1021/acsami.3c15490
• Publication Date: 2023-11-15T16:52:26Z
• Authors: Vitalii Kavun; Evgeny Uslamin; Bart van der Linden; Stefano Canossa; Andrey Goryachev; Emma E. Bos; Jara Garcia Santa...; Grigory Smolentsev; Eveliina Repo; Monique A. van de...
• Keywords: XANES; X-ray absorption spectroscopy

Titanium-based metal-organic framework, NH2-MIL-125(Ti), has been widely investigated for photocatalytic applications but low activity in the hydrogen evolution reaction (HER). In this work, we show a one-step low-cost postmodification of NH2-MIL-125(Ti) via impregnation Co(NO3)2. The resulting Co@NH2-MIL-125(Ti) with embedded single-site CoII species, confirmed by XPS and XAS measurements, shows enhanced under visible light exposure. increased H2 production is likely triggered presence active CoI transient sites detected upon collection pump-flow-probe XANES spectra. Furthermore, both photocatalysts demonstrated drastic increase HER performance after consecutive reuse while maintaining their structural integrity consistent production. Via thorough characterization, revealed two mechanisms formation highly proton reduction sites: nondestructive linker elimination coordinatively unsaturated Ti restructuring single sites. Overall, straightforward manner confinement cocatalysts within offers stable visible-light-responsive photocatalyst.